Preparation of V-doped AZO thin films and ZnO nanorods on V-doped AZO thin films by hydrothermal process

The growth mechanisms of ZnO nanorods (NRs) on sputtered Al-doped ZnO (AZO) and V-doped AZO (V:AZO) thin films are studied in this work. Firstly, the microstructure of the AZO and V:AZO thin films was investigated by XRD. We found that V-dopants retard the crystallization (grain growth) and enlarge the d-spacing of the (0002) plane of the V:AZO thin films. ZnO NRs were prepared on the AZO and V:AZO thin film substrates by the hydrothermal method. Vertically aligned ZnO NRs were grown on the pure AZO thin film substrate. With incorporating V-dopants, the growth direction of ZnO NRs grown on the V:AZO thin films is highly influenced by the concentration of the V-doping. The V-doping causes the random growth direction of ZnO NRs. XRD and SEM analysis indicate that the growth behavior of ZnO NRs depends on the microstructure of the surface grains of the AZO and V:AZO thin film substrates. A growth mechanism of ZnO NRs on the AZO and V:AZO thin film substrates is proposed in this work.